Merge pull request #44 from golemcloud/special-method-for-pollable

Generating a promise() function for Pollable

Author: vigoo

crates/wasm-rquickjs/src/imports.rs

@@ -332,6 +332,27 @@ fn generate_import_module(
             }
         }
 
+        let mut special_methods = Vec::new();
+        if resource_name == "pollable"
+            && &import.name == "poll"
+            && import
+                .package_name
+                .as_ref()
+                .map(|p| format!("{}:{}", p.namespace, p.name))
+                == Some("wasi:io".to_string())
+        {
+            special_methods.push(quote! {
+                pub async fn promise(&mut self) -> () {
+                    let js_state = crate::internal::get_js_state();
+                    let reactor = js_state.reactor.borrow().clone().unwrap();
+
+                    let pollable = self.inner.take().expect("Resource has already been disposed");
+                    let pollable: wasi::io::poll::Pollable = unsafe { wasi::io::poll::Pollable::from_handle(pollable.take_handle()) };
+                    reactor.wait_for(pollable).await;
+                }
+            });
+        }
+
         let rquickjs_class =
             generate_rquickjs_class_module(resource_name, &resource_name_ident, &resource_name_lit);
 
@@ -354,6 +375,8 @@ fn generate_import_module(
                 pub fn __dispose(&mut self) {
                     let _ = self.inner.take();
                 }
+
+                #(#special_methods)*
             }
 
             impl<'js> rquickjs::IntoJs<'js> for #bindgen_path {

examples/pollable/src/pollable.js

@@ -0,0 +1,12 @@
+
+import * as poll from 'wasi:io/poll@0.2.3';
+import * as monotonicClock from 'wasi:clocks/monotonic-clock@0.2.3';
+
+export const test = async () => {
+    let nanos = BigInt(2 * 1000 * 1000 * 1000);
+    let pollable = monotonicClock.subscribeDuration(nanos)
+    let before = monotonicClock.now();
+    await pollable.promise();
+    let after = monotonicClock.now();
+    return after - before;
+};

examples/pollable/wit/deps/clocks/monotonic-clock.wit

@@ -0,0 +1,50 @@
+package wasi:clocks@0.2.3;
+/// WASI Monotonic Clock is a clock API intended to let users measure elapsed
+/// time.
+///
+/// It is intended to be portable at least between Unix-family platforms and
+/// Windows.
+///
+/// A monotonic clock is a clock which has an unspecified initial value, and
+/// successive reads of the clock will produce non-decreasing values.
+@since(version = 0.2.0)
+interface monotonic-clock {
+    @since(version = 0.2.0)
+    use wasi:io/poll@0.2.3.{pollable};
+
+    /// An instant in time, in nanoseconds. An instant is relative to an
+    /// unspecified initial value, and can only be compared to instances from
+    /// the same monotonic-clock.
+    @since(version = 0.2.0)
+    type instant = u64;
+
+    /// A duration of time, in nanoseconds.
+    @since(version = 0.2.0)
+    type duration = u64;
+
+    /// Read the current value of the clock.
+    ///
+    /// The clock is monotonic, therefore calling this function repeatedly will
+    /// produce a sequence of non-decreasing values.
+    @since(version = 0.2.0)
+    now: func() -> instant;
+
+    /// Query the resolution of the clock. Returns the duration of time
+    /// corresponding to a clock tick.
+    @since(version = 0.2.0)
+    resolution: func() -> duration;
+
+    /// Create a `pollable` which will resolve once the specified instant
+    /// has occurred.
+    @since(version = 0.2.0)
+    subscribe-instant: func(
+        when: instant,
+    ) -> pollable;
+
+    /// Create a `pollable` that will resolve after the specified duration has
+    /// elapsed from the time this function is invoked.
+    @since(version = 0.2.0)
+    subscribe-duration: func(
+        when: duration,
+    ) -> pollable;
+}

examples/pollable/wit/deps/clocks/timezone.wit

@@ -0,0 +1,55 @@
+package wasi:clocks@0.2.3;
+
+@unstable(feature = clocks-timezone)
+interface timezone {
+    @unstable(feature = clocks-timezone)
+    use wall-clock.{datetime};
+
+    /// Return information needed to display the given `datetime`. This includes
+    /// the UTC offset, the time zone name, and a flag indicating whether
+    /// daylight saving time is active.
+    ///
+    /// If the timezone cannot be determined for the given `datetime`, return a
+    /// `timezone-display` for `UTC` with a `utc-offset` of 0 and no daylight
+    /// saving time.
+    @unstable(feature = clocks-timezone)
+    display: func(when: datetime) -> timezone-display;
+
+    /// The same as `display`, but only return the UTC offset.
+    @unstable(feature = clocks-timezone)
+    utc-offset: func(when: datetime) -> s32;
+
+    /// Information useful for displaying the timezone of a specific `datetime`.
+    ///
+    /// This information may vary within a single `timezone` to reflect daylight
+    /// saving time adjustments.
+    @unstable(feature = clocks-timezone)
+    record timezone-display {
+        /// The number of seconds difference between UTC time and the local
+        /// time of the timezone.
+        ///
+        /// The returned value will always be less than 86400 which is the
+        /// number of seconds in a day (24*60*60).
+        ///
+        /// In implementations that do not expose an actual time zone, this
+        /// should return 0.
+        utc-offset: s32,
+
+        /// The abbreviated name of the timezone to display to a user. The name
+        /// `UTC` indicates Coordinated Universal Time. Otherwise, this should
+        /// reference local standards for the name of the time zone.
+        ///
+        /// In implementations that do not expose an actual time zone, this
+        /// should be the string `UTC`.
+        ///
+        /// In time zones that do not have an applicable name, a formatted
+        /// representation of the UTC offset may be returned, such as `-04:00`.
+        name: string,
+
+        /// Whether daylight saving time is active.
+        ///
+        /// In implementations that do not expose an actual time zone, this
+        /// should return false.
+        in-daylight-saving-time: bool,
+    }
+}

examples/pollable/wit/deps/clocks/wall-clock.wit

@@ -0,0 +1,46 @@
+package wasi:clocks@0.2.3;
+/// WASI Wall Clock is a clock API intended to let users query the current
+/// time. The name "wall" makes an analogy to a "clock on the wall", which
+/// is not necessarily monotonic as it may be reset.
+///
+/// It is intended to be portable at least between Unix-family platforms and
+/// Windows.
+///
+/// A wall clock is a clock which measures the date and time according to
+/// some external reference.
+///
+/// External references may be reset, so this clock is not necessarily
+/// monotonic, making it unsuitable for measuring elapsed time.
+///
+/// It is intended for reporting the current date and time for humans.
+@since(version = 0.2.0)
+interface wall-clock {
+    /// A time and date in seconds plus nanoseconds.
+    @since(version = 0.2.0)
+    record datetime {
+        seconds: u64,
+        nanoseconds: u32,
+    }
+
+    /// Read the current value of the clock.
+    ///
+    /// This clock is not monotonic, therefore calling this function repeatedly
+    /// will not necessarily produce a sequence of non-decreasing values.
+    ///
+    /// The returned timestamps represent the number of seconds since
+    /// 1970-01-01T00:00:00Z, also known as [POSIX's Seconds Since the Epoch],
+    /// also known as [Unix Time].
+    ///
+    /// The nanoseconds field of the output is always less than 1000000000.
+    ///
+    /// [POSIX's Seconds Since the Epoch]: https://pubs.opengroup.org/onlinepubs/9699919799/xrat/V4_xbd_chap04.html#tag_21_04_16
+    /// [Unix Time]: https://en.wikipedia.org/wiki/Unix_time
+    @since(version = 0.2.0)
+    now: func() -> datetime;
+
+    /// Query the resolution of the clock.
+    ///
+    /// The nanoseconds field of the output is always less than 1000000000.
+    @since(version = 0.2.0)
+    resolution: func() -> datetime;
+}

examples/pollable/wit/deps/clocks/world.wit

@@ -0,0 +1,11 @@
+package wasi:clocks@0.2.3;
+
+@since(version = 0.2.0)
+world imports {
+    @since(version = 0.2.0)
+    import monotonic-clock;
+    @since(version = 0.2.0)
+    import wall-clock;
+    @unstable(feature = clocks-timezone)
+    import timezone;
+}

examples/pollable/wit/deps/io/error.wit

@@ -0,0 +1,34 @@
+package wasi:io@0.2.3;
+
+@since(version = 0.2.0)
+interface error {
+    /// A resource which represents some error information.
+    ///
+    /// The only method provided by this resource is `to-debug-string`,
+    /// which provides some human-readable information about the error.
+    ///
+    /// In the `wasi:io` package, this resource is returned through the
+    /// `wasi:io/streams/stream-error` type.
+    ///
+    /// To provide more specific error information, other interfaces may
+    /// offer functions to "downcast" this error into more specific types. For example,
+    /// errors returned from streams derived from filesystem types can be described using
+    /// the filesystem's own error-code type. This is done using the function
+    /// `wasi:filesystem/types/filesystem-error-code`, which takes a `borrow<error>`
+    /// parameter and returns an `option<wasi:filesystem/types/error-code>`.
+    ///
+    /// The set of functions which can "downcast" an `error` into a more
+    /// concrete type is open.
+    @since(version = 0.2.0)
+    resource error {
+        /// Returns a string that is suitable to assist humans in debugging
+        /// this error.
+        ///
+        /// WARNING: The returned string should not be consumed mechanically!
+        /// It may change across platforms, hosts, or other implementation
+        /// details. Parsing this string is a major platform-compatibility
+        /// hazard.
+        @since(version = 0.2.0)
+        to-debug-string: func() -> string;
+    }
+}

examples/pollable/wit/deps/io/poll.wit

@@ -0,0 +1,47 @@
+package wasi:io@0.2.3;
+
+/// A poll API intended to let users wait for I/O events on multiple handles
+/// at once.
+@since(version = 0.2.0)
+interface poll {
+    /// `pollable` represents a single I/O event which may be ready, or not.
+    @since(version = 0.2.0)
+    resource pollable {
+
+      /// Return the readiness of a pollable. This function never blocks.
+      ///
+      /// Returns `true` when the pollable is ready, and `false` otherwise.
+      @since(version = 0.2.0)
+      ready: func() -> bool;
+
+      /// `block` returns immediately if the pollable is ready, and otherwise
+      /// blocks until ready.
+      ///
+      /// This function is equivalent to calling `poll.poll` on a list
+      /// containing only this pollable.
+      @since(version = 0.2.0)
+      block: func();
+    }
+
+    /// Poll for completion on a set of pollables.
+    ///
+    /// This function takes a list of pollables, which identify I/O sources of
+    /// interest, and waits until one or more of the events is ready for I/O.
+    ///
+    /// The result `list<u32>` contains one or more indices of handles in the
+    /// argument list that is ready for I/O.
+    ///
+    /// This function traps if either:
+    /// - the list is empty, or:
+    /// - the list contains more elements than can be indexed with a `u32` value.
+    ///
+    /// A timeout can be implemented by adding a pollable from the
+    /// wasi-clocks API to the list.
+    ///
+    /// This function does not return a `result`; polling in itself does not
+    /// do any I/O so it doesn't fail. If any of the I/O sources identified by
+    /// the pollables has an error, it is indicated by marking the source as
+    /// being ready for I/O.
+    @since(version = 0.2.0)
+    poll: func(in: list<borrow<pollable>>) -> list<u32>;
+}